Comparative study of acid-treated and alkali-treated carbonised Kapok–fibres for oil/water absorption system

Abstract Kapok predominantly utilized as an adsorbent in removing wastewater such as dye, oil and heavy metals. However, a comparative study between acid-treated and alkali-treated carbonized Kapok fibers has not been carried out in detail. In this study, as-made Kapok fibers were carbonized and subsequently undergo acid (HCL) and alkali (NaOH) treatment. The resultant treated Kapok fibers were characterized using Fourier transform infrared (FTIR) spectroscopy, Elemental Analyzer (EA) and Thermogravimetric Analysis (TGA). As-made carbonized Kapok fibers were tested with oil/water absorption model system. A reduction of band intensity at 1740 cm−1 and 1245 cm−1 occurred for NaOH treated sample compared with HCL. The composition of carbon in Kapok fiber increased after carbonization treatment using NaOH (62.42%) and HCL (66.15%) compared with untreated (0.17%). For oil/water absorption system, the result indicated that HCL-treated Kapok fibre was the highest absorption on 28.10 gg−1 diesel, 27.28 gg−1 petrol and 39.84 gg−1 for used vegetable oil respectively in comparison with NaoH-treated and as-made carbonized Kapor fibers. In conclusion, modification of the surface of carbonized Kapok fibers could significantly alter its textural properties which could enhance its oil absorptive behavior.